ELDERS, MUSSELS, AND FISHERIES IN THE WADDEN SEA - CONTINUOUS CONFLICTS OR RELAXED RELATIONS

Elder, Somateria mollissima, and mussel, Mytilus edulis, stocks were s tudied in the Wadden Sea of Schleswig-Holstein with respect to interac tions with mussel fisheries. Mussel fisheries take place by means of 2 ,800 ha of bottom cultures, with seed mussels taken from natural beds. Fisheries have a marked influence on total mussel stocks. The amount of mussels found on the culture lots and annual landings of up to 40,0 00 tons may exceed natural stocks. About 130,000 elders use the Wadden Sea of Schleswig-Holstein for moulting and on average about 70,000 st ay over the winter. Mussel cultures are estimated to provide on averag e about 10 to 20% of the food of elders. However, the number of winter ing elders utilizing the cultures varies in relation to the amount and size of the mussels present and ranges from 10 to 60%. No evidence wa s found that elders have a measurable impact on the yield of the cultu res and no response of elder numbers to increasing culturing could be detected. Mussel fisheries are regarded as a potential threat to elder s, because they might reduce total mussel stocks considerably and migh t affect elder numbers in years of low bivalve stocks. It is recommend ed to regulate the fisheries in order to prevent overfishing of mussel stocks, which recently happened in other parts of the Wadden Sea.